Vehicle signal control circuitry



March 10, 1970 VEHICLE SIGNAL CONTROL CIRCUITRY Filed March 27, 1967 J. PINEAU ET AL 3,500,314

United States Patent 3,500,314 VEHICLE SIGNAL CONTROL CIRCUITRY Jean Pineau and Francois Peroy, Billancourt, France, assignors to Regie Nationale des Usines Renault, Billancourt, France Filed Mar. 27, 1967, Ser. No. 626,213 Claims priority, applicggitiill rance, Apr. 8, 1966,

US. Cl. 340--74 1 Claim ABSTRACT OF THE DISCLOSURE A device for controlling a plurality of elements, circuits or the like, comprising a plurality of branch circuits connected in parallel to the terminals of a source of unidirectional current. Each branch circuit comprises two component elements in series, namely, a signal means and a contact responsive to one of the elements to be controlled. At least two signal means are put in parallel by connecting each conductor common to the two component elements of one of said branch circuits through a unidirectional conducting element disposed in the passing direction, to the same point, and that said common point is connected to the other terminal of the source of current through an auxiliary contact.

This invention relates to the control of circuits by a same or different number of signal means, and is concerned more particularly with devices wherein the combination of said signal means with unidirectional conducting elements permits identifying the faulty circuit, if any.

In fact, devices are already known which permit simultaneously controlling a plurality of electrical circuits from a single signal lamp. However, this arrangement is inadequate for detecting or ascertaining the origin of the failure or defect. The same also applies to any device wherein the number of signal lamps is not the same as that of the circuits to be controlled.

It is an important object of the present invention to connect a plurality of signal lamps to a same common point so that these lamps can be lighted simultaneously by closing a contact connected to said point, while making the individual operation .of each lamp independent of that of the other lamps, this possibility being permitted by the unidirectional conducting element disposed in the passing direction, each signal lamp being connected through this element to the common point. In fact, this element permits the collective operation of all the lamps connected to said common point, and the separate operation of each lamp only if the contact directly associated therewith is closed.

This device may be roughly considered as affording the individual operation of a signal lamp within the interdependence of its collective operation.

A device according to this invention for controlling a plurality of elements, circuits or apparatus, comprises, in parallel relationship to the terminals of unidirectional source of current, branch circuits each comprising two component elements disposed in series, one signal means and a contact. The contact is responsive to one of said elements to be controlled. The device is characterised in that at least two signal means are connected in parallel by connecting the conductors already connecting these signal means to the contact of their branch circuit, through a unidirectional conducting element disposed in the passing direction, to a same common point, and that said last-named common point is connected to the other ice terminal of the source of current through an auxiliary contact.

The scope and advantageous features of this invention will appear more clearly as the following description proceeds with reference to the attached drawing of which the single figure illustrates in diagram form a storage battery 1 constituting a source of current having its positive terminal connected through a switch 2 to a pair of lamps 3 and 4 mounted in series respectively with contacts 5 and 6 connected in turn to the other terminal of said battery. The conductors connecting each lamp to the relevant contact, that is, those extending from 3 to 5 and from 4 to 6, are connected through semi-conductor diodes 7 and 8 respectively to a common point connected through the contact 9 to the negative terminal of the storage battery 1 grounded at 10.

The contacts 5 and 6 control circuits in which only a particularly exceptional failure can close the contacts to light lamp 3 or 4.

The parameters to be controlled may be for example the temperature of the fluid in the cooling system of an internal combustion engine, the level of a liquid in a tank, or the thickness of brake linings. Contacts 5 and 6 close when the two parameters respectively controlled thereby exceed their preset or predetermined limit.

On the other hand, contact 9 is closed initially by actuating the switch 2, and opens only when the circuit to be controlled is operating, this contact 9 being reclosed only in case of faulty operation of said circuit. This arrangement is applicable for example to the oil-pressure gauge of an internal combustion engine. As a result, when switch 2 (consisting for example of the ignition switch of an automotive vehicle) is closed, contact 9 being already closed since the oil pressure is zero when the engine is inoperative, lamps 3 and 4 will light up automatically as a consequence of the passage of current and their proper operation is thus verified; then they go out when the oil pressure attains its normal value.

Then, during normal operating conditions, three cases may arise:

A failure takes place in the circuit controlled by the contact 5: this contact 5 is thus closed and only lamp 3 is lighted;

A failure takes place in the circuit controlled by contact 6: this contact is thus closed and only lamp 4 is lighted;

A failure originates in the circuit controlled by contact 9, so that both lamps 3 and 4 are lighted, as the current flows through the diodes 7 and 8 disposed in the passing direction.

The semi-conductors 7 and 8 are either independent and consists of standard diodes, or integrated in a common case comprising a semi-conductor disk constituting a common base having on its free surface two alloy zones bounded in relation to each other, constituting two separate emitters and each provided with a connecting conductor.

This device is advantageous in that it permits controlling three parameters by means of only two lamps. The only uncertainty would result, most improbably, from a simultaneous failure occurring in the two circuits controlled by said contacts 5 and 6, thus closing these contacts and lighting both lamps 3 and 4 simultaneously, and closing contact 9.

This device is also advantageous in that it permits verifying the proper condition of signal lamps likely to be lighted only in the case of an extremely rare failure, which, in the case of an automotive vehicle, constitutes a complementary safety element.

The same result, that is, the simultaneous checking of all the signal lamps, may be obtained when controlling a greater number of parameters.

Thus, a given number n of parameters may be controlled by means of (rv1) lamps connected in series, each lamp being connected to one of the (n1) contacts similar to contacts 5 and 6 of the above-described example: then each lamp is connected through a diode to one point then common to the (n1) lamps, by utilizing (n-1) diodes in the passing direction and connecting said common point to the other terminal of the source of direct or rectified current through a contact of same type as contact 9; under these conditions, all the lamps of the device can be vertified automatically and simultaneously. In case no parameter similar to the one controlled by contact 9 were available, the simultaneous vertification of all the lamps may be made by substituting for the contact S! a fugitive contact whereby the desired contact can be established at any time, notably each time the device is started.

It will be readily understood that if desired the checking can 'be applied to only one fraction of the signal lamps; for example, those performing the control functions considered as essential for the proper operation of the controlled apparatus or equipmeit; in this case, the

tactors may also be of the relay type without contacts,

comprising semiconductors with control electrodes.

Alternately, a single lamp may be connected through different diodes to a plurality of common points, with one contact associated with each point. In this case, the

number of signal lamps to be utilized may be reduced in comparison with the number of parameters to be controlled, by resorting to diflerent combinations of lamp lighting circuits for identifying a failure, the lamps being lighted not only separately but if desired by pairs.

We claim:

1. A device for controlling a plurality of elements, circuits and the like, in particular on automotive vehicles, comprising a plurality of alarm circuits arranged in parallel with the terminals of a source of unidirectional current, each said alarm circuit having a signal lamp and a switch closing in response to any defect in the element to be controlled, an additional parallel circuit connected to each of the alarm circuits by means of diodes connected to points located between the lamps and the switches of said alarm circuits in the direction passing towards said additional circuit, which additional circuit also comprises a signal switch normally closed upon being placed in operation and for a short time after placing the entire device in operation, and a main switch arranged between the current source and a terminal common to all of said parallel circuits so that the closing of said main switch lights up all the lamps which then are put out by the opening of the additional switch, the various alarm circuits being then ready for operation.

References Cited UNITED STATES PATENTS 3,349,387 10/1967 Sicard 340-332 X HAROLD I. PITTS, Primary Examiner U.S. Cl. X.R. 

